Epigenetics deals with modifications in gene expression, without altering the underlying DNA sequence. Genomic imprinting is a complex epigenetic phenomenon that refers to parent-of-origin-specific gene expression. Beckwith–Wiedemann syndrome (BWS) and Silver–Russell syndrome (SRS) are congenital imprinting disorders with mirror opposite alterations at the genomic loci in 11p15.5 and opposite phenotypes. BWS and SRS are important imprinting disorders with the increase of knowledge of genetic and epigenetic mechanisms. Altered expression of the imprinted genes in 11p15.5, especially IGF2 and CDKN1C , affects fetal and postnatal growth. A wide range of imprinting defects at multiple loci, instead of a restricted locus, has been shown in some patients with either BWS or SRS. The development of new high-throughput assays will make it possible to allow accurate diagnosis, personalized therapy, and informative genetic counseling.
Introduction
The Imprinted 11p15 Region
Beckwith–Wiedemann Syndrome
Silver–Russell Syndrome
Genotype-Phenotype Correlations in Beckwith–Wiedemann Syndrome and Silver–Russell Syndrome
Multilocus Imprinting Disturbances
Conclusion
References